Speed-regulator for power transmission.



N0. 805,748. l PATENTED NOV. 28, 1905.

' O. PFANSOHMIDT.

SPEED REGULATOR FOR POWER TRANSMISSION. APPLICATION FILED MAYs, 1905.

M4 :S2M my 15%5? UNTTED STATES PATENT oEEIoE.

CHARLES PFANSCHMIDT, OF CHICAGO, ILLINOIS, ASSIGNOR TO VIBRAS- SAGECOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLI- NOIS.

Specification of Letters Patent.

Patented Nov. 28, 1905.

Application filed May 3, 1905. Serial Nol 258,578.

To all whom it m/a/y concern:

Be it known that I, CHARLES PEANSCHMIDT, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Speed-Regulators forPower Transmission,of which the following is a speciiication. y

This invention is intended more especially for use with electric motorsor other powerdriven mechanism in which the motor maintains a constantspeed; and'` the object of the invention is to provide a simple andeasilyadjusted mechanism for regulating the speed imparted from theconstantly-driven motor to a iieXible shaft or other power-transmittingmechanism.

Another object of the invention is to so construct the parts that themechanism may be applied to motors of any ordinary construction withoutchanging or modifying the operating mechanism, and the invention isparticularly adapted for use in connection with massage or dentalimplements in which a small electric motor is ordinarily employed andfitted to impart rotation to a flexible shaft connected with a dental ormassage tool in the hands of the operator.

In devices of this general class it is highly desirable that a quickregulation of speed may be made without interfering with the operationof the motor, which remains substantially constant at all times.

Another object of the invention is to so regulate the adjustingmechanism that it will be impossible to overload the motor when started,which would tend to impair or burn out the motor and render it useless.

The invention consists in the features of construction and combinationof parts hereinafter described and claimed.

In the drawings, illustrating the invention, Figure 1 is a sideelevation of an electric motor, showing the speed-regulator in position;and Fig. 2, a similar front view.

The motor comprises a casing 1, having passed therethrough a power-shaft2, having thereon an armature 3, contacted by brushes 4 of any suitablecharacter. Upon the powershaft is mounted a grooved pulley 5, carrying aiiexible belt 6, and immediately above the power-pulley 5 is aregulating-pulley 7, around which the belt passes for the purpose ofimparting rotation thereto. The regulating-pulley is mounted upon astud-shaft 8, mounted`in journal-boxes 9, formed in the ends of a yoke10, which embraces the regulating-pulley and is rigidly secured to theend of a spring-plate 11, iiXed at its opposite end to a block 12,rigidly mounted on a suitable part of the motor-casing. The outer end ofthe stud-shaft 8 has secured thereto a iiexible shaft 13, which isadapted to transmit rotation to a dental or massage tool or othersimilar implement. The spring plate is formed to have a sufiicientresiliency to hold the belt taut or distended under normal conditions,thereby imparting the entire rotation of the power-pulley to theregulating-pulley; but when it is desirable to reduce the speed impartedto the rotary shaft the spring-plate is depressed under tension byvmeans of a thumb-screw 14, screw-threaded through a standard 15,rigidly mounted on the casing of the motor orl other suitable part ofthe mechanism. By screwing down the thumbscrew the plate 11 isdepressed, bringing the power-pulley and regulating-pulley closertogether, thereby loosening up the tension exerted on the belt andallowing said belt to slip to aconsiderable degree as the motor isoperated. The resiliency of the spring-plate should be suiicient toimpart the maximum speed of revolution; `but it is not advisable to havethis resiliency such as to overload the motor and bring it to a stop byreason of the tension on the belt. By initially determining the maXimumvtension of the spring-plate it will be impossible for the operator tooverload the motor, for the reason that after the spring-plate hasreached its normal position any further retraction of the thumb-screw bythe operation will have no effect whatever on the position of the plate.By screwing down the thumbscrew, however, the belt-pulley can beloosened to a very considerable degree and the speed of the flexibleshaft regulated from nothing up to the maximum degree of revolution.rlhis adjustment can be instantly made without interfering with theoperation of the motor itself and without subjecting it to the wear andtear due to continued regulation of its mechanism.

What I regard as new, and desire to secure by Letters Patent, is-

1. In a speed-regulator, the combination of a pow er-shaft, apower-pulley secured thereto, a Spring-plate,a regulating-pulley,journals on IOO IOS

the spring-plate. in which the regulating-pulley is mounted, a beltpassing around the pulleys and means for adjusting the position of thespring-plate to vary the distance between the pulleys and vary thetension exerted on the belt, substantially as described.

2. yIn a speed-regulator, the combination of a power-shaft, a pulleymounted thereon, a power-transmission shaft, a regulating-pulley mountedthereon, ayoke in which the powertransmission shaft is journaled, aspring-plate rigidly secured at one end, and having a yoke secured toits free end, and a set-screw adapted to bear against the spring-plateto regulate its position and vary the distance between the pulleys andthe tension exerted on the belt, substantially as described.

3. yIn a speed-regulator, the combination of a power-shaft, a pulleymounted thereon, a power-transmission shaft, a regulating-pulley mountedthereon, a yoke in which the powertransmission shaft is journaled, aspring-plate rigidly secured at one end, and having a yoke secured toits free end, a set-screw adapted to bear against the spring-plate toregulate its position and vary the distance between the pulleys and thetension exerted on the belt, thespring-plate having a resiliency to holdthe belt taut when normal but to prevent the stoppage of the power-shaftby an excessive tension on the belt, substantially as described.

4. In a speed-regulator, the combination of a motor having projectingtherefrom a powershaft, a grooved power-pulley rigidly mounted on theshaft, a spring-plate secured to the Inotor at one end and having at itsfree end a yoke, a grooved regulating-pulley mounted on apower-transmission shaft, a thumb-screw adapted to bear against thespring-plate and regulate'tbe distance between the two pulleys, and apower-transinission belt passing around the pulleys, substantially asdescribed.

CHARLES PFANSCHMIDT. Witnesses: SAMUEL W. BANNING, WALKER BANNING.

